Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/mm/shmem.c
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
File MIME type: text/plain
File size: 58951 byte(s)
Tag kernel26-2.6.12-alx-r9
1 | /* |
2 | * Resizable virtual memory filesystem for Linux. |
3 | * |
4 | * Copyright (C) 2000 Linus Torvalds. |
5 | * 2000 Transmeta Corp. |
6 | * 2000-2001 Christoph Rohland |
7 | * 2000-2001 SAP AG |
8 | * 2002 Red Hat Inc. |
9 | * Copyright (C) 2002-2004 Hugh Dickins. |
10 | * Copyright (C) 2002-2004 VERITAS Software Corporation. |
11 | * Copyright (C) 2004 Andi Kleen, SuSE Labs |
12 | * |
13 | * Extended attribute support for tmpfs: |
14 | * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net> |
15 | * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> |
16 | * |
17 | * This file is released under the GPL. |
18 | */ |
19 | |
20 | /* |
21 | * This virtual memory filesystem is heavily based on the ramfs. It |
22 | * extends ramfs by the ability to use swap and honor resource limits |
23 | * which makes it a completely usable filesystem. |
24 | */ |
25 | |
26 | #include <linux/config.h> |
27 | #include <linux/module.h> |
28 | #include <linux/init.h> |
29 | #include <linux/devfs_fs_kernel.h> |
30 | #include <linux/fs.h> |
31 | #include <linux/mm.h> |
32 | #include <linux/mman.h> |
33 | #include <linux/file.h> |
34 | #include <linux/swap.h> |
35 | #include <linux/pagemap.h> |
36 | #include <linux/string.h> |
37 | #include <linux/slab.h> |
38 | #include <linux/backing-dev.h> |
39 | #include <linux/shmem_fs.h> |
40 | #include <linux/mount.h> |
41 | #include <linux/writeback.h> |
42 | #include <linux/vfs.h> |
43 | #include <linux/blkdev.h> |
44 | #include <linux/security.h> |
45 | #include <linux/swapops.h> |
46 | #include <linux/mempolicy.h> |
47 | #include <linux/namei.h> |
48 | #include <linux/xattr.h> |
49 | #include <asm/uaccess.h> |
50 | #include <asm/div64.h> |
51 | #include <asm/pgtable.h> |
52 | |
53 | /* This magic number is used in glibc for posix shared memory */ |
54 | #define TMPFS_MAGIC 0x01021994 |
55 | |
56 | #define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long)) |
57 | #define ENTRIES_PER_PAGEPAGE (ENTRIES_PER_PAGE*ENTRIES_PER_PAGE) |
58 | #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) |
59 | |
60 | #define SHMEM_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1)) |
61 | #define SHMEM_MAX_BYTES ((unsigned long long)SHMEM_MAX_INDEX << PAGE_CACHE_SHIFT) |
62 | |
63 | #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT) |
64 | |
65 | /* info->flags needs VM_flags to handle pagein/truncate races efficiently */ |
66 | #define SHMEM_PAGEIN VM_READ |
67 | #define SHMEM_TRUNCATE VM_WRITE |
68 | |
69 | /* Definition to limit shmem_truncate's steps between cond_rescheds */ |
70 | #define LATENCY_LIMIT 64 |
71 | |
72 | /* Pretend that each entry is of this size in directory's i_size */ |
73 | #define BOGO_DIRENT_SIZE 20 |
74 | |
75 | /* Keep swapped page count in private field of indirect struct page */ |
76 | #define nr_swapped private |
77 | |
78 | /* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */ |
79 | enum sgp_type { |
80 | SGP_QUICK, /* don't try more than file page cache lookup */ |
81 | SGP_READ, /* don't exceed i_size, don't allocate page */ |
82 | SGP_CACHE, /* don't exceed i_size, may allocate page */ |
83 | SGP_WRITE, /* may exceed i_size, may allocate page */ |
84 | }; |
85 | |
86 | static int shmem_getpage(struct inode *inode, unsigned long idx, |
87 | struct page **pagep, enum sgp_type sgp, int *type); |
88 | |
89 | static inline struct page *shmem_dir_alloc(unsigned int gfp_mask) |
90 | { |
91 | /* |
92 | * The above definition of ENTRIES_PER_PAGE, and the use of |
93 | * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE: |
94 | * might be reconsidered if it ever diverges from PAGE_SIZE. |
95 | */ |
96 | return alloc_pages(gfp_mask, PAGE_CACHE_SHIFT-PAGE_SHIFT); |
97 | } |
98 | |
99 | static inline void shmem_dir_free(struct page *page) |
100 | { |
101 | __free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT); |
102 | } |
103 | |
104 | static struct page **shmem_dir_map(struct page *page) |
105 | { |
106 | return (struct page **)kmap_atomic(page, KM_USER0); |
107 | } |
108 | |
109 | static inline void shmem_dir_unmap(struct page **dir) |
110 | { |
111 | kunmap_atomic(dir, KM_USER0); |
112 | } |
113 | |
114 | static swp_entry_t *shmem_swp_map(struct page *page) |
115 | { |
116 | return (swp_entry_t *)kmap_atomic(page, KM_USER1); |
117 | } |
118 | |
119 | static inline void shmem_swp_balance_unmap(void) |
120 | { |
121 | /* |
122 | * When passing a pointer to an i_direct entry, to code which |
123 | * also handles indirect entries and so will shmem_swp_unmap, |
124 | * we must arrange for the preempt count to remain in balance. |
125 | * What kmap_atomic of a lowmem page does depends on config |
126 | * and architecture, so pretend to kmap_atomic some lowmem page. |
127 | */ |
128 | (void) kmap_atomic(ZERO_PAGE(0), KM_USER1); |
129 | } |
130 | |
131 | static inline void shmem_swp_unmap(swp_entry_t *entry) |
132 | { |
133 | kunmap_atomic(entry, KM_USER1); |
134 | } |
135 | |
136 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) |
137 | { |
138 | return sb->s_fs_info; |
139 | } |
140 | |
141 | /* |
142 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, |
143 | * for shared memory and for shared anonymous (/dev/zero) mappings |
144 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), |
145 | * consistent with the pre-accounting of private mappings ... |
146 | */ |
147 | static inline int shmem_acct_size(unsigned long flags, loff_t size) |
148 | { |
149 | return (flags & VM_ACCOUNT)? |
150 | security_vm_enough_memory(VM_ACCT(size)): 0; |
151 | } |
152 | |
153 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) |
154 | { |
155 | if (flags & VM_ACCOUNT) |
156 | vm_unacct_memory(VM_ACCT(size)); |
157 | } |
158 | |
159 | /* |
160 | * ... whereas tmpfs objects are accounted incrementally as |
161 | * pages are allocated, in order to allow huge sparse files. |
162 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, |
163 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. |
164 | */ |
165 | static inline int shmem_acct_block(unsigned long flags) |
166 | { |
167 | return (flags & VM_ACCOUNT)? |
168 | 0: security_vm_enough_memory(VM_ACCT(PAGE_CACHE_SIZE)); |
169 | } |
170 | |
171 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) |
172 | { |
173 | if (!(flags & VM_ACCOUNT)) |
174 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); |
175 | } |
176 | |
177 | static struct super_operations shmem_ops; |
178 | static struct address_space_operations shmem_aops; |
179 | static struct file_operations shmem_file_operations; |
180 | static struct inode_operations shmem_inode_operations; |
181 | static struct inode_operations shmem_dir_inode_operations; |
182 | static struct inode_operations shmem_special_inode_operations; |
183 | static struct vm_operations_struct shmem_vm_ops; |
184 | |
185 | static struct backing_dev_info shmem_backing_dev_info = { |
186 | .ra_pages = 0, /* No readahead */ |
187 | .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, |
188 | .unplug_io_fn = default_unplug_io_fn, |
189 | }; |
190 | |
191 | static LIST_HEAD(shmem_swaplist); |
192 | static DEFINE_SPINLOCK(shmem_swaplist_lock); |
193 | |
194 | static void shmem_free_blocks(struct inode *inode, long pages) |
195 | { |
196 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
197 | if (sbinfo) { |
198 | spin_lock(&sbinfo->stat_lock); |
199 | sbinfo->free_blocks += pages; |
200 | inode->i_blocks -= pages*BLOCKS_PER_PAGE; |
201 | spin_unlock(&sbinfo->stat_lock); |
202 | } |
203 | } |
204 | |
205 | /* |
206 | * shmem_recalc_inode - recalculate the size of an inode |
207 | * |
208 | * @inode: inode to recalc |
209 | * |
210 | * We have to calculate the free blocks since the mm can drop |
211 | * undirtied hole pages behind our back. |
212 | * |
213 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped |
214 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) |
215 | * |
216 | * It has to be called with the spinlock held. |
217 | */ |
218 | static void shmem_recalc_inode(struct inode *inode) |
219 | { |
220 | struct shmem_inode_info *info = SHMEM_I(inode); |
221 | long freed; |
222 | |
223 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; |
224 | if (freed > 0) { |
225 | info->alloced -= freed; |
226 | shmem_unacct_blocks(info->flags, freed); |
227 | shmem_free_blocks(inode, freed); |
228 | } |
229 | } |
230 | |
231 | /* |
232 | * shmem_swp_entry - find the swap vector position in the info structure |
233 | * |
234 | * @info: info structure for the inode |
235 | * @index: index of the page to find |
236 | * @page: optional page to add to the structure. Has to be preset to |
237 | * all zeros |
238 | * |
239 | * If there is no space allocated yet it will return NULL when |
240 | * page is NULL, else it will use the page for the needed block, |
241 | * setting it to NULL on return to indicate that it has been used. |
242 | * |
243 | * The swap vector is organized the following way: |
244 | * |
245 | * There are SHMEM_NR_DIRECT entries directly stored in the |
246 | * shmem_inode_info structure. So small files do not need an addional |
247 | * allocation. |
248 | * |
249 | * For pages with index > SHMEM_NR_DIRECT there is the pointer |
250 | * i_indirect which points to a page which holds in the first half |
251 | * doubly indirect blocks, in the second half triple indirect blocks: |
252 | * |
253 | * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the |
254 | * following layout (for SHMEM_NR_DIRECT == 16): |
255 | * |
256 | * i_indirect -> dir --> 16-19 |
257 | * | +-> 20-23 |
258 | * | |
259 | * +-->dir2 --> 24-27 |
260 | * | +-> 28-31 |
261 | * | +-> 32-35 |
262 | * | +-> 36-39 |
263 | * | |
264 | * +-->dir3 --> 40-43 |
265 | * +-> 44-47 |
266 | * +-> 48-51 |
267 | * +-> 52-55 |
268 | */ |
269 | static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page) |
270 | { |
271 | unsigned long offset; |
272 | struct page **dir; |
273 | struct page *subdir; |
274 | |
275 | if (index < SHMEM_NR_DIRECT) { |
276 | shmem_swp_balance_unmap(); |
277 | return info->i_direct+index; |
278 | } |
279 | if (!info->i_indirect) { |
280 | if (page) { |
281 | info->i_indirect = *page; |
282 | *page = NULL; |
283 | } |
284 | return NULL; /* need another page */ |
285 | } |
286 | |
287 | index -= SHMEM_NR_DIRECT; |
288 | offset = index % ENTRIES_PER_PAGE; |
289 | index /= ENTRIES_PER_PAGE; |
290 | dir = shmem_dir_map(info->i_indirect); |
291 | |
292 | if (index >= ENTRIES_PER_PAGE/2) { |
293 | index -= ENTRIES_PER_PAGE/2; |
294 | dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE; |
295 | index %= ENTRIES_PER_PAGE; |
296 | subdir = *dir; |
297 | if (!subdir) { |
298 | if (page) { |
299 | *dir = *page; |
300 | *page = NULL; |
301 | } |
302 | shmem_dir_unmap(dir); |
303 | return NULL; /* need another page */ |
304 | } |
305 | shmem_dir_unmap(dir); |
306 | dir = shmem_dir_map(subdir); |
307 | } |
308 | |
309 | dir += index; |
310 | subdir = *dir; |
311 | if (!subdir) { |
312 | if (!page || !(subdir = *page)) { |
313 | shmem_dir_unmap(dir); |
314 | return NULL; /* need a page */ |
315 | } |
316 | *dir = subdir; |
317 | *page = NULL; |
318 | } |
319 | shmem_dir_unmap(dir); |
320 | return shmem_swp_map(subdir) + offset; |
321 | } |
322 | |
323 | static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value) |
324 | { |
325 | long incdec = value? 1: -1; |
326 | |
327 | entry->val = value; |
328 | info->swapped += incdec; |
329 | if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) |
330 | kmap_atomic_to_page(entry)->nr_swapped += incdec; |
331 | } |
332 | |
333 | /* |
334 | * shmem_swp_alloc - get the position of the swap entry for the page. |
335 | * If it does not exist allocate the entry. |
336 | * |
337 | * @info: info structure for the inode |
338 | * @index: index of the page to find |
339 | * @sgp: check and recheck i_size? skip allocation? |
340 | */ |
341 | static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp) |
342 | { |
343 | struct inode *inode = &info->vfs_inode; |
344 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
345 | struct page *page = NULL; |
346 | swp_entry_t *entry; |
347 | |
348 | if (sgp != SGP_WRITE && |
349 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
350 | return ERR_PTR(-EINVAL); |
351 | |
352 | while (!(entry = shmem_swp_entry(info, index, &page))) { |
353 | if (sgp == SGP_READ) |
354 | return shmem_swp_map(ZERO_PAGE(0)); |
355 | /* |
356 | * Test free_blocks against 1 not 0, since we have 1 data |
357 | * page (and perhaps indirect index pages) yet to allocate: |
358 | * a waste to allocate index if we cannot allocate data. |
359 | */ |
360 | if (sbinfo) { |
361 | spin_lock(&sbinfo->stat_lock); |
362 | if (sbinfo->free_blocks <= 1) { |
363 | spin_unlock(&sbinfo->stat_lock); |
364 | return ERR_PTR(-ENOSPC); |
365 | } |
366 | sbinfo->free_blocks--; |
367 | inode->i_blocks += BLOCKS_PER_PAGE; |
368 | spin_unlock(&sbinfo->stat_lock); |
369 | } |
370 | |
371 | spin_unlock(&info->lock); |
372 | page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping) | __GFP_ZERO); |
373 | if (page) { |
374 | page->nr_swapped = 0; |
375 | } |
376 | spin_lock(&info->lock); |
377 | |
378 | if (!page) { |
379 | shmem_free_blocks(inode, 1); |
380 | return ERR_PTR(-ENOMEM); |
381 | } |
382 | if (sgp != SGP_WRITE && |
383 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { |
384 | entry = ERR_PTR(-EINVAL); |
385 | break; |
386 | } |
387 | if (info->next_index <= index) |
388 | info->next_index = index + 1; |
389 | } |
390 | if (page) { |
391 | /* another task gave its page, or truncated the file */ |
392 | shmem_free_blocks(inode, 1); |
393 | shmem_dir_free(page); |
394 | } |
395 | if (info->next_index <= index && !IS_ERR(entry)) |
396 | info->next_index = index + 1; |
397 | return entry; |
398 | } |
399 | |
400 | /* |
401 | * shmem_free_swp - free some swap entries in a directory |
402 | * |
403 | * @dir: pointer to the directory |
404 | * @edir: pointer after last entry of the directory |
405 | */ |
406 | static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir) |
407 | { |
408 | swp_entry_t *ptr; |
409 | int freed = 0; |
410 | |
411 | for (ptr = dir; ptr < edir; ptr++) { |
412 | if (ptr->val) { |
413 | free_swap_and_cache(*ptr); |
414 | *ptr = (swp_entry_t){0}; |
415 | freed++; |
416 | } |
417 | } |
418 | return freed; |
419 | } |
420 | |
421 | static int shmem_map_and_free_swp(struct page *subdir, |
422 | int offset, int limit, struct page ***dir) |
423 | { |
424 | swp_entry_t *ptr; |
425 | int freed = 0; |
426 | |
427 | ptr = shmem_swp_map(subdir); |
428 | for (; offset < limit; offset += LATENCY_LIMIT) { |
429 | int size = limit - offset; |
430 | if (size > LATENCY_LIMIT) |
431 | size = LATENCY_LIMIT; |
432 | freed += shmem_free_swp(ptr+offset, ptr+offset+size); |
433 | if (need_resched()) { |
434 | shmem_swp_unmap(ptr); |
435 | if (*dir) { |
436 | shmem_dir_unmap(*dir); |
437 | *dir = NULL; |
438 | } |
439 | cond_resched(); |
440 | ptr = shmem_swp_map(subdir); |
441 | } |
442 | } |
443 | shmem_swp_unmap(ptr); |
444 | return freed; |
445 | } |
446 | |
447 | static void shmem_free_pages(struct list_head *next) |
448 | { |
449 | struct page *page; |
450 | int freed = 0; |
451 | |
452 | do { |
453 | page = container_of(next, struct page, lru); |
454 | next = next->next; |
455 | shmem_dir_free(page); |
456 | freed++; |
457 | if (freed >= LATENCY_LIMIT) { |
458 | cond_resched(); |
459 | freed = 0; |
460 | } |
461 | } while (next); |
462 | } |
463 | |
464 | static void shmem_truncate(struct inode *inode) |
465 | { |
466 | struct shmem_inode_info *info = SHMEM_I(inode); |
467 | unsigned long idx; |
468 | unsigned long size; |
469 | unsigned long limit; |
470 | unsigned long stage; |
471 | unsigned long diroff; |
472 | struct page **dir; |
473 | struct page *topdir; |
474 | struct page *middir; |
475 | struct page *subdir; |
476 | swp_entry_t *ptr; |
477 | LIST_HEAD(pages_to_free); |
478 | long nr_pages_to_free = 0; |
479 | long nr_swaps_freed = 0; |
480 | int offset; |
481 | int freed; |
482 | |
483 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; |
484 | idx = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
485 | if (idx >= info->next_index) |
486 | return; |
487 | |
488 | spin_lock(&info->lock); |
489 | info->flags |= SHMEM_TRUNCATE; |
490 | limit = info->next_index; |
491 | info->next_index = idx; |
492 | topdir = info->i_indirect; |
493 | if (topdir && idx <= SHMEM_NR_DIRECT) { |
494 | info->i_indirect = NULL; |
495 | nr_pages_to_free++; |
496 | list_add(&topdir->lru, &pages_to_free); |
497 | } |
498 | spin_unlock(&info->lock); |
499 | |
500 | if (info->swapped && idx < SHMEM_NR_DIRECT) { |
501 | ptr = info->i_direct; |
502 | size = limit; |
503 | if (size > SHMEM_NR_DIRECT) |
504 | size = SHMEM_NR_DIRECT; |
505 | nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size); |
506 | } |
507 | if (!topdir) |
508 | goto done2; |
509 | |
510 | BUG_ON(limit <= SHMEM_NR_DIRECT); |
511 | limit -= SHMEM_NR_DIRECT; |
512 | idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0; |
513 | offset = idx % ENTRIES_PER_PAGE; |
514 | idx -= offset; |
515 | |
516 | dir = shmem_dir_map(topdir); |
517 | stage = ENTRIES_PER_PAGEPAGE/2; |
518 | if (idx < ENTRIES_PER_PAGEPAGE/2) { |
519 | middir = topdir; |
520 | diroff = idx/ENTRIES_PER_PAGE; |
521 | } else { |
522 | dir += ENTRIES_PER_PAGE/2; |
523 | dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE; |
524 | while (stage <= idx) |
525 | stage += ENTRIES_PER_PAGEPAGE; |
526 | middir = *dir; |
527 | if (*dir) { |
528 | diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) % |
529 | ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE; |
530 | if (!diroff && !offset) { |
531 | *dir = NULL; |
532 | nr_pages_to_free++; |
533 | list_add(&middir->lru, &pages_to_free); |
534 | } |
535 | shmem_dir_unmap(dir); |
536 | dir = shmem_dir_map(middir); |
537 | } else { |
538 | diroff = 0; |
539 | offset = 0; |
540 | idx = stage; |
541 | } |
542 | } |
543 | |
544 | for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) { |
545 | if (unlikely(idx == stage)) { |
546 | shmem_dir_unmap(dir); |
547 | dir = shmem_dir_map(topdir) + |
548 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; |
549 | while (!*dir) { |
550 | dir++; |
551 | idx += ENTRIES_PER_PAGEPAGE; |
552 | if (idx >= limit) |
553 | goto done1; |
554 | } |
555 | stage = idx + ENTRIES_PER_PAGEPAGE; |
556 | middir = *dir; |
557 | *dir = NULL; |
558 | nr_pages_to_free++; |
559 | list_add(&middir->lru, &pages_to_free); |
560 | shmem_dir_unmap(dir); |
561 | cond_resched(); |
562 | dir = shmem_dir_map(middir); |
563 | diroff = 0; |
564 | } |
565 | subdir = dir[diroff]; |
566 | if (subdir && subdir->nr_swapped) { |
567 | size = limit - idx; |
568 | if (size > ENTRIES_PER_PAGE) |
569 | size = ENTRIES_PER_PAGE; |
570 | freed = shmem_map_and_free_swp(subdir, |
571 | offset, size, &dir); |
572 | if (!dir) |
573 | dir = shmem_dir_map(middir); |
574 | nr_swaps_freed += freed; |
575 | if (offset) |
576 | spin_lock(&info->lock); |
577 | subdir->nr_swapped -= freed; |
578 | if (offset) |
579 | spin_unlock(&info->lock); |
580 | BUG_ON(subdir->nr_swapped > offset); |
581 | } |
582 | if (offset) |
583 | offset = 0; |
584 | else if (subdir) { |
585 | dir[diroff] = NULL; |
586 | nr_pages_to_free++; |
587 | list_add(&subdir->lru, &pages_to_free); |
588 | } |
589 | } |
590 | done1: |
591 | shmem_dir_unmap(dir); |
592 | done2: |
593 | if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) { |
594 | /* |
595 | * Call truncate_inode_pages again: racing shmem_unuse_inode |
596 | * may have swizzled a page in from swap since vmtruncate or |
597 | * generic_delete_inode did it, before we lowered next_index. |
598 | * Also, though shmem_getpage checks i_size before adding to |
599 | * cache, no recheck after: so fix the narrow window there too. |
600 | */ |
601 | truncate_inode_pages(inode->i_mapping, inode->i_size); |
602 | } |
603 | |
604 | spin_lock(&info->lock); |
605 | info->flags &= ~SHMEM_TRUNCATE; |
606 | info->swapped -= nr_swaps_freed; |
607 | if (nr_pages_to_free) |
608 | shmem_free_blocks(inode, nr_pages_to_free); |
609 | shmem_recalc_inode(inode); |
610 | spin_unlock(&info->lock); |
611 | |
612 | /* |
613 | * Empty swap vector directory pages to be freed? |
614 | */ |
615 | if (!list_empty(&pages_to_free)) { |
616 | pages_to_free.prev->next = NULL; |
617 | shmem_free_pages(pages_to_free.next); |
618 | } |
619 | } |
620 | |
621 | static int shmem_notify_change(struct dentry *dentry, struct iattr *attr) |
622 | { |
623 | struct inode *inode = dentry->d_inode; |
624 | struct page *page = NULL; |
625 | int error; |
626 | |
627 | if (attr->ia_valid & ATTR_SIZE) { |
628 | if (attr->ia_size < inode->i_size) { |
629 | /* |
630 | * If truncating down to a partial page, then |
631 | * if that page is already allocated, hold it |
632 | * in memory until the truncation is over, so |
633 | * truncate_partial_page cannnot miss it were |
634 | * it assigned to swap. |
635 | */ |
636 | if (attr->ia_size & (PAGE_CACHE_SIZE-1)) { |
637 | (void) shmem_getpage(inode, |
638 | attr->ia_size>>PAGE_CACHE_SHIFT, |
639 | &page, SGP_READ, NULL); |
640 | } |
641 | /* |
642 | * Reset SHMEM_PAGEIN flag so that shmem_truncate can |
643 | * detect if any pages might have been added to cache |
644 | * after truncate_inode_pages. But we needn't bother |
645 | * if it's being fully truncated to zero-length: the |
646 | * nrpages check is efficient enough in that case. |
647 | */ |
648 | if (attr->ia_size) { |
649 | struct shmem_inode_info *info = SHMEM_I(inode); |
650 | spin_lock(&info->lock); |
651 | info->flags &= ~SHMEM_PAGEIN; |
652 | spin_unlock(&info->lock); |
653 | } |
654 | } |
655 | } |
656 | |
657 | error = inode_change_ok(inode, attr); |
658 | if (!error) |
659 | error = inode_setattr(inode, attr); |
660 | if (page) |
661 | page_cache_release(page); |
662 | return error; |
663 | } |
664 | |
665 | static void shmem_delete_inode(struct inode *inode) |
666 | { |
667 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
668 | struct shmem_inode_info *info = SHMEM_I(inode); |
669 | |
670 | if (inode->i_op->truncate == shmem_truncate) { |
671 | shmem_unacct_size(info->flags, inode->i_size); |
672 | inode->i_size = 0; |
673 | shmem_truncate(inode); |
674 | if (!list_empty(&info->swaplist)) { |
675 | spin_lock(&shmem_swaplist_lock); |
676 | list_del_init(&info->swaplist); |
677 | spin_unlock(&shmem_swaplist_lock); |
678 | } |
679 | } |
680 | if (sbinfo) { |
681 | BUG_ON(inode->i_blocks); |
682 | spin_lock(&sbinfo->stat_lock); |
683 | sbinfo->free_inodes++; |
684 | spin_unlock(&sbinfo->stat_lock); |
685 | } |
686 | clear_inode(inode); |
687 | } |
688 | |
689 | static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir) |
690 | { |
691 | swp_entry_t *ptr; |
692 | |
693 | for (ptr = dir; ptr < edir; ptr++) { |
694 | if (ptr->val == entry.val) |
695 | return ptr - dir; |
696 | } |
697 | return -1; |
698 | } |
699 | |
700 | static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page) |
701 | { |
702 | struct inode *inode; |
703 | unsigned long idx; |
704 | unsigned long size; |
705 | unsigned long limit; |
706 | unsigned long stage; |
707 | struct page **dir; |
708 | struct page *subdir; |
709 | swp_entry_t *ptr; |
710 | int offset; |
711 | |
712 | idx = 0; |
713 | ptr = info->i_direct; |
714 | spin_lock(&info->lock); |
715 | limit = info->next_index; |
716 | size = limit; |
717 | if (size > SHMEM_NR_DIRECT) |
718 | size = SHMEM_NR_DIRECT; |
719 | offset = shmem_find_swp(entry, ptr, ptr+size); |
720 | if (offset >= 0) { |
721 | shmem_swp_balance_unmap(); |
722 | goto found; |
723 | } |
724 | if (!info->i_indirect) |
725 | goto lost2; |
726 | |
727 | dir = shmem_dir_map(info->i_indirect); |
728 | stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2; |
729 | |
730 | for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) { |
731 | if (unlikely(idx == stage)) { |
732 | shmem_dir_unmap(dir-1); |
733 | dir = shmem_dir_map(info->i_indirect) + |
734 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; |
735 | while (!*dir) { |
736 | dir++; |
737 | idx += ENTRIES_PER_PAGEPAGE; |
738 | if (idx >= limit) |
739 | goto lost1; |
740 | } |
741 | stage = idx + ENTRIES_PER_PAGEPAGE; |
742 | subdir = *dir; |
743 | shmem_dir_unmap(dir); |
744 | dir = shmem_dir_map(subdir); |
745 | } |
746 | subdir = *dir; |
747 | if (subdir && subdir->nr_swapped) { |
748 | ptr = shmem_swp_map(subdir); |
749 | size = limit - idx; |
750 | if (size > ENTRIES_PER_PAGE) |
751 | size = ENTRIES_PER_PAGE; |
752 | offset = shmem_find_swp(entry, ptr, ptr+size); |
753 | if (offset >= 0) { |
754 | shmem_dir_unmap(dir); |
755 | goto found; |
756 | } |
757 | shmem_swp_unmap(ptr); |
758 | } |
759 | } |
760 | lost1: |
761 | shmem_dir_unmap(dir-1); |
762 | lost2: |
763 | spin_unlock(&info->lock); |
764 | return 0; |
765 | found: |
766 | idx += offset; |
767 | inode = &info->vfs_inode; |
768 | if (move_from_swap_cache(page, idx, inode->i_mapping) == 0) { |
769 | info->flags |= SHMEM_PAGEIN; |
770 | shmem_swp_set(info, ptr + offset, 0); |
771 | } |
772 | shmem_swp_unmap(ptr); |
773 | spin_unlock(&info->lock); |
774 | /* |
775 | * Decrement swap count even when the entry is left behind: |
776 | * try_to_unuse will skip over mms, then reincrement count. |
777 | */ |
778 | swap_free(entry); |
779 | return 1; |
780 | } |
781 | |
782 | /* |
783 | * shmem_unuse() search for an eventually swapped out shmem page. |
784 | */ |
785 | int shmem_unuse(swp_entry_t entry, struct page *page) |
786 | { |
787 | struct list_head *p, *next; |
788 | struct shmem_inode_info *info; |
789 | int found = 0; |
790 | |
791 | spin_lock(&shmem_swaplist_lock); |
792 | list_for_each_safe(p, next, &shmem_swaplist) { |
793 | info = list_entry(p, struct shmem_inode_info, swaplist); |
794 | if (!info->swapped) |
795 | list_del_init(&info->swaplist); |
796 | else if (shmem_unuse_inode(info, entry, page)) { |
797 | /* move head to start search for next from here */ |
798 | list_move_tail(&shmem_swaplist, &info->swaplist); |
799 | found = 1; |
800 | break; |
801 | } |
802 | } |
803 | spin_unlock(&shmem_swaplist_lock); |
804 | return found; |
805 | } |
806 | |
807 | /* |
808 | * Move the page from the page cache to the swap cache. |
809 | */ |
810 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) |
811 | { |
812 | struct shmem_inode_info *info; |
813 | swp_entry_t *entry, swap; |
814 | struct address_space *mapping; |
815 | unsigned long index; |
816 | struct inode *inode; |
817 | |
818 | BUG_ON(!PageLocked(page)); |
819 | BUG_ON(page_mapped(page)); |
820 | |
821 | mapping = page->mapping; |
822 | index = page->index; |
823 | inode = mapping->host; |
824 | info = SHMEM_I(inode); |
825 | if (info->flags & VM_LOCKED) |
826 | goto redirty; |
827 | swap = get_swap_page(); |
828 | if (!swap.val) |
829 | goto redirty; |
830 | |
831 | spin_lock(&info->lock); |
832 | shmem_recalc_inode(inode); |
833 | if (index >= info->next_index) { |
834 | BUG_ON(!(info->flags & SHMEM_TRUNCATE)); |
835 | goto unlock; |
836 | } |
837 | entry = shmem_swp_entry(info, index, NULL); |
838 | BUG_ON(!entry); |
839 | BUG_ON(entry->val); |
840 | |
841 | if (move_to_swap_cache(page, swap) == 0) { |
842 | shmem_swp_set(info, entry, swap.val); |
843 | shmem_swp_unmap(entry); |
844 | spin_unlock(&info->lock); |
845 | if (list_empty(&info->swaplist)) { |
846 | spin_lock(&shmem_swaplist_lock); |
847 | /* move instead of add in case we're racing */ |
848 | list_move_tail(&info->swaplist, &shmem_swaplist); |
849 | spin_unlock(&shmem_swaplist_lock); |
850 | } |
851 | unlock_page(page); |
852 | return 0; |
853 | } |
854 | |
855 | shmem_swp_unmap(entry); |
856 | unlock: |
857 | spin_unlock(&info->lock); |
858 | swap_free(swap); |
859 | redirty: |
860 | set_page_dirty(page); |
861 | return WRITEPAGE_ACTIVATE; /* Return with the page locked */ |
862 | } |
863 | |
864 | #ifdef CONFIG_NUMA |
865 | static struct page *shmem_swapin_async(struct shared_policy *p, |
866 | swp_entry_t entry, unsigned long idx) |
867 | { |
868 | struct page *page; |
869 | struct vm_area_struct pvma; |
870 | |
871 | /* Create a pseudo vma that just contains the policy */ |
872 | memset(&pvma, 0, sizeof(struct vm_area_struct)); |
873 | pvma.vm_end = PAGE_SIZE; |
874 | pvma.vm_pgoff = idx; |
875 | pvma.vm_policy = mpol_shared_policy_lookup(p, idx); |
876 | page = read_swap_cache_async(entry, &pvma, 0); |
877 | mpol_free(pvma.vm_policy); |
878 | return page; |
879 | } |
880 | |
881 | struct page *shmem_swapin(struct shmem_inode_info *info, swp_entry_t entry, |
882 | unsigned long idx) |
883 | { |
884 | struct shared_policy *p = &info->policy; |
885 | int i, num; |
886 | struct page *page; |
887 | unsigned long offset; |
888 | |
889 | num = valid_swaphandles(entry, &offset); |
890 | for (i = 0; i < num; offset++, i++) { |
891 | page = shmem_swapin_async(p, |
892 | swp_entry(swp_type(entry), offset), idx); |
893 | if (!page) |
894 | break; |
895 | page_cache_release(page); |
896 | } |
897 | lru_add_drain(); /* Push any new pages onto the LRU now */ |
898 | return shmem_swapin_async(p, entry, idx); |
899 | } |
900 | |
901 | static struct page * |
902 | shmem_alloc_page(unsigned long gfp, struct shmem_inode_info *info, |
903 | unsigned long idx) |
904 | { |
905 | struct vm_area_struct pvma; |
906 | struct page *page; |
907 | |
908 | memset(&pvma, 0, sizeof(struct vm_area_struct)); |
909 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); |
910 | pvma.vm_pgoff = idx; |
911 | pvma.vm_end = PAGE_SIZE; |
912 | page = alloc_page_vma(gfp | __GFP_ZERO, &pvma, 0); |
913 | mpol_free(pvma.vm_policy); |
914 | return page; |
915 | } |
916 | #else |
917 | static inline struct page * |
918 | shmem_swapin(struct shmem_inode_info *info,swp_entry_t entry,unsigned long idx) |
919 | { |
920 | swapin_readahead(entry, 0, NULL); |
921 | return read_swap_cache_async(entry, NULL, 0); |
922 | } |
923 | |
924 | static inline struct page * |
925 | shmem_alloc_page(unsigned int __nocast gfp,struct shmem_inode_info *info, |
926 | unsigned long idx) |
927 | { |
928 | return alloc_page(gfp | __GFP_ZERO); |
929 | } |
930 | #endif |
931 | |
932 | /* |
933 | * shmem_getpage - either get the page from swap or allocate a new one |
934 | * |
935 | * If we allocate a new one we do not mark it dirty. That's up to the |
936 | * vm. If we swap it in we mark it dirty since we also free the swap |
937 | * entry since a page cannot live in both the swap and page cache |
938 | */ |
939 | static int shmem_getpage(struct inode *inode, unsigned long idx, |
940 | struct page **pagep, enum sgp_type sgp, int *type) |
941 | { |
942 | struct address_space *mapping = inode->i_mapping; |
943 | struct shmem_inode_info *info = SHMEM_I(inode); |
944 | struct shmem_sb_info *sbinfo; |
945 | struct page *filepage = *pagep; |
946 | struct page *swappage; |
947 | swp_entry_t *entry; |
948 | swp_entry_t swap; |
949 | int error; |
950 | |
951 | if (idx >= SHMEM_MAX_INDEX) |
952 | return -EFBIG; |
953 | /* |
954 | * Normally, filepage is NULL on entry, and either found |
955 | * uptodate immediately, or allocated and zeroed, or read |
956 | * in under swappage, which is then assigned to filepage. |
957 | * But shmem_prepare_write passes in a locked filepage, |
958 | * which may be found not uptodate by other callers too, |
959 | * and may need to be copied from the swappage read in. |
960 | */ |
961 | repeat: |
962 | if (!filepage) |
963 | filepage = find_lock_page(mapping, idx); |
964 | if (filepage && PageUptodate(filepage)) |
965 | goto done; |
966 | error = 0; |
967 | if (sgp == SGP_QUICK) |
968 | goto failed; |
969 | |
970 | spin_lock(&info->lock); |
971 | shmem_recalc_inode(inode); |
972 | entry = shmem_swp_alloc(info, idx, sgp); |
973 | if (IS_ERR(entry)) { |
974 | spin_unlock(&info->lock); |
975 | error = PTR_ERR(entry); |
976 | goto failed; |
977 | } |
978 | swap = *entry; |
979 | |
980 | if (swap.val) { |
981 | /* Look it up and read it in.. */ |
982 | swappage = lookup_swap_cache(swap); |
983 | if (!swappage) { |
984 | shmem_swp_unmap(entry); |
985 | spin_unlock(&info->lock); |
986 | /* here we actually do the io */ |
987 | if (type && *type == VM_FAULT_MINOR) { |
988 | inc_page_state(pgmajfault); |
989 | *type = VM_FAULT_MAJOR; |
990 | } |
991 | swappage = shmem_swapin(info, swap, idx); |
992 | if (!swappage) { |
993 | spin_lock(&info->lock); |
994 | entry = shmem_swp_alloc(info, idx, sgp); |
995 | if (IS_ERR(entry)) |
996 | error = PTR_ERR(entry); |
997 | else { |
998 | if (entry->val == swap.val) |
999 | error = -ENOMEM; |
1000 | shmem_swp_unmap(entry); |
1001 | } |
1002 | spin_unlock(&info->lock); |
1003 | if (error) |
1004 | goto failed; |
1005 | goto repeat; |
1006 | } |
1007 | wait_on_page_locked(swappage); |
1008 | page_cache_release(swappage); |
1009 | goto repeat; |
1010 | } |
1011 | |
1012 | /* We have to do this with page locked to prevent races */ |
1013 | if (TestSetPageLocked(swappage)) { |
1014 | shmem_swp_unmap(entry); |
1015 | spin_unlock(&info->lock); |
1016 | wait_on_page_locked(swappage); |
1017 | page_cache_release(swappage); |
1018 | goto repeat; |
1019 | } |
1020 | if (PageWriteback(swappage)) { |
1021 | shmem_swp_unmap(entry); |
1022 | spin_unlock(&info->lock); |
1023 | wait_on_page_writeback(swappage); |
1024 | unlock_page(swappage); |
1025 | page_cache_release(swappage); |
1026 | goto repeat; |
1027 | } |
1028 | if (!PageUptodate(swappage)) { |
1029 | shmem_swp_unmap(entry); |
1030 | spin_unlock(&info->lock); |
1031 | unlock_page(swappage); |
1032 | page_cache_release(swappage); |
1033 | error = -EIO; |
1034 | goto failed; |
1035 | } |
1036 | |
1037 | if (filepage) { |
1038 | shmem_swp_set(info, entry, 0); |
1039 | shmem_swp_unmap(entry); |
1040 | delete_from_swap_cache(swappage); |
1041 | spin_unlock(&info->lock); |
1042 | copy_highpage(filepage, swappage); |
1043 | unlock_page(swappage); |
1044 | page_cache_release(swappage); |
1045 | flush_dcache_page(filepage); |
1046 | SetPageUptodate(filepage); |
1047 | set_page_dirty(filepage); |
1048 | swap_free(swap); |
1049 | } else if (!(error = move_from_swap_cache( |
1050 | swappage, idx, mapping))) { |
1051 | info->flags |= SHMEM_PAGEIN; |
1052 | shmem_swp_set(info, entry, 0); |
1053 | shmem_swp_unmap(entry); |
1054 | spin_unlock(&info->lock); |
1055 | filepage = swappage; |
1056 | swap_free(swap); |
1057 | } else { |
1058 | shmem_swp_unmap(entry); |
1059 | spin_unlock(&info->lock); |
1060 | unlock_page(swappage); |
1061 | page_cache_release(swappage); |
1062 | if (error == -ENOMEM) { |
1063 | /* let kswapd refresh zone for GFP_ATOMICs */ |
1064 | blk_congestion_wait(WRITE, HZ/50); |
1065 | } |
1066 | goto repeat; |
1067 | } |
1068 | } else if (sgp == SGP_READ && !filepage) { |
1069 | shmem_swp_unmap(entry); |
1070 | filepage = find_get_page(mapping, idx); |
1071 | if (filepage && |
1072 | (!PageUptodate(filepage) || TestSetPageLocked(filepage))) { |
1073 | spin_unlock(&info->lock); |
1074 | wait_on_page_locked(filepage); |
1075 | page_cache_release(filepage); |
1076 | filepage = NULL; |
1077 | goto repeat; |
1078 | } |
1079 | spin_unlock(&info->lock); |
1080 | } else { |
1081 | shmem_swp_unmap(entry); |
1082 | sbinfo = SHMEM_SB(inode->i_sb); |
1083 | if (sbinfo) { |
1084 | spin_lock(&sbinfo->stat_lock); |
1085 | if (sbinfo->free_blocks == 0 || |
1086 | shmem_acct_block(info->flags)) { |
1087 | spin_unlock(&sbinfo->stat_lock); |
1088 | spin_unlock(&info->lock); |
1089 | error = -ENOSPC; |
1090 | goto failed; |
1091 | } |
1092 | sbinfo->free_blocks--; |
1093 | inode->i_blocks += BLOCKS_PER_PAGE; |
1094 | spin_unlock(&sbinfo->stat_lock); |
1095 | } else if (shmem_acct_block(info->flags)) { |
1096 | spin_unlock(&info->lock); |
1097 | error = -ENOSPC; |
1098 | goto failed; |
1099 | } |
1100 | |
1101 | if (!filepage) { |
1102 | spin_unlock(&info->lock); |
1103 | filepage = shmem_alloc_page(mapping_gfp_mask(mapping), |
1104 | info, |
1105 | idx); |
1106 | if (!filepage) { |
1107 | shmem_unacct_blocks(info->flags, 1); |
1108 | shmem_free_blocks(inode, 1); |
1109 | error = -ENOMEM; |
1110 | goto failed; |
1111 | } |
1112 | |
1113 | spin_lock(&info->lock); |
1114 | entry = shmem_swp_alloc(info, idx, sgp); |
1115 | if (IS_ERR(entry)) |
1116 | error = PTR_ERR(entry); |
1117 | else { |
1118 | swap = *entry; |
1119 | shmem_swp_unmap(entry); |
1120 | } |
1121 | if (error || swap.val || 0 != add_to_page_cache_lru( |
1122 | filepage, mapping, idx, GFP_ATOMIC)) { |
1123 | spin_unlock(&info->lock); |
1124 | page_cache_release(filepage); |
1125 | shmem_unacct_blocks(info->flags, 1); |
1126 | shmem_free_blocks(inode, 1); |
1127 | filepage = NULL; |
1128 | if (error) |
1129 | goto failed; |
1130 | goto repeat; |
1131 | } |
1132 | info->flags |= SHMEM_PAGEIN; |
1133 | } |
1134 | |
1135 | info->alloced++; |
1136 | spin_unlock(&info->lock); |
1137 | flush_dcache_page(filepage); |
1138 | SetPageUptodate(filepage); |
1139 | } |
1140 | done: |
1141 | if (*pagep != filepage) { |
1142 | unlock_page(filepage); |
1143 | *pagep = filepage; |
1144 | } |
1145 | return 0; |
1146 | |
1147 | failed: |
1148 | if (*pagep != filepage) { |
1149 | unlock_page(filepage); |
1150 | page_cache_release(filepage); |
1151 | } |
1152 | return error; |
1153 | } |
1154 | |
1155 | struct page *shmem_nopage(struct vm_area_struct *vma, unsigned long address, int *type) |
1156 | { |
1157 | struct inode *inode = vma->vm_file->f_dentry->d_inode; |
1158 | struct page *page = NULL; |
1159 | unsigned long idx; |
1160 | int error; |
1161 | |
1162 | idx = (address - vma->vm_start) >> PAGE_SHIFT; |
1163 | idx += vma->vm_pgoff; |
1164 | idx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT; |
1165 | if (((loff_t) idx << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
1166 | return NOPAGE_SIGBUS; |
1167 | |
1168 | error = shmem_getpage(inode, idx, &page, SGP_CACHE, type); |
1169 | if (error) |
1170 | return (error == -ENOMEM)? NOPAGE_OOM: NOPAGE_SIGBUS; |
1171 | |
1172 | mark_page_accessed(page); |
1173 | return page; |
1174 | } |
1175 | |
1176 | static int shmem_populate(struct vm_area_struct *vma, |
1177 | unsigned long addr, unsigned long len, |
1178 | pgprot_t prot, unsigned long pgoff, int nonblock) |
1179 | { |
1180 | struct inode *inode = vma->vm_file->f_dentry->d_inode; |
1181 | struct mm_struct *mm = vma->vm_mm; |
1182 | enum sgp_type sgp = nonblock? SGP_QUICK: SGP_CACHE; |
1183 | unsigned long size; |
1184 | |
1185 | size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; |
1186 | if (pgoff >= size || pgoff + (len >> PAGE_SHIFT) > size) |
1187 | return -EINVAL; |
1188 | |
1189 | while ((long) len > 0) { |
1190 | struct page *page = NULL; |
1191 | int err; |
1192 | /* |
1193 | * Will need changing if PAGE_CACHE_SIZE != PAGE_SIZE |
1194 | */ |
1195 | err = shmem_getpage(inode, pgoff, &page, sgp, NULL); |
1196 | if (err) |
1197 | return err; |
1198 | if (page) { |
1199 | mark_page_accessed(page); |
1200 | err = install_page(mm, vma, addr, page, prot); |
1201 | if (err) { |
1202 | page_cache_release(page); |
1203 | return err; |
1204 | } |
1205 | } else if (nonblock) { |
1206 | err = install_file_pte(mm, vma, addr, pgoff, prot); |
1207 | if (err) |
1208 | return err; |
1209 | } |
1210 | |
1211 | len -= PAGE_SIZE; |
1212 | addr += PAGE_SIZE; |
1213 | pgoff++; |
1214 | } |
1215 | return 0; |
1216 | } |
1217 | |
1218 | #ifdef CONFIG_NUMA |
1219 | int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new) |
1220 | { |
1221 | struct inode *i = vma->vm_file->f_dentry->d_inode; |
1222 | return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new); |
1223 | } |
1224 | |
1225 | struct mempolicy * |
1226 | shmem_get_policy(struct vm_area_struct *vma, unsigned long addr) |
1227 | { |
1228 | struct inode *i = vma->vm_file->f_dentry->d_inode; |
1229 | unsigned long idx; |
1230 | |
1231 | idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; |
1232 | return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx); |
1233 | } |
1234 | #endif |
1235 | |
1236 | int shmem_lock(struct file *file, int lock, struct user_struct *user) |
1237 | { |
1238 | struct inode *inode = file->f_dentry->d_inode; |
1239 | struct shmem_inode_info *info = SHMEM_I(inode); |
1240 | int retval = -ENOMEM; |
1241 | |
1242 | spin_lock(&info->lock); |
1243 | if (lock && !(info->flags & VM_LOCKED)) { |
1244 | if (!user_shm_lock(inode->i_size, user)) |
1245 | goto out_nomem; |
1246 | info->flags |= VM_LOCKED; |
1247 | } |
1248 | if (!lock && (info->flags & VM_LOCKED) && user) { |
1249 | user_shm_unlock(inode->i_size, user); |
1250 | info->flags &= ~VM_LOCKED; |
1251 | } |
1252 | retval = 0; |
1253 | out_nomem: |
1254 | spin_unlock(&info->lock); |
1255 | return retval; |
1256 | } |
1257 | |
1258 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1259 | { |
1260 | file_accessed(file); |
1261 | vma->vm_ops = &shmem_vm_ops; |
1262 | return 0; |
1263 | } |
1264 | |
1265 | static struct inode * |
1266 | shmem_get_inode(struct super_block *sb, int mode, dev_t dev) |
1267 | { |
1268 | struct inode *inode; |
1269 | struct shmem_inode_info *info; |
1270 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
1271 | |
1272 | if (sbinfo) { |
1273 | spin_lock(&sbinfo->stat_lock); |
1274 | if (!sbinfo->free_inodes) { |
1275 | spin_unlock(&sbinfo->stat_lock); |
1276 | return NULL; |
1277 | } |
1278 | sbinfo->free_inodes--; |
1279 | spin_unlock(&sbinfo->stat_lock); |
1280 | } |
1281 | |
1282 | inode = new_inode(sb); |
1283 | if (inode) { |
1284 | inode->i_mode = mode; |
1285 | inode->i_uid = current->fsuid; |
1286 | inode->i_gid = current->fsgid; |
1287 | inode->i_blksize = PAGE_CACHE_SIZE; |
1288 | inode->i_blocks = 0; |
1289 | inode->i_mapping->a_ops = &shmem_aops; |
1290 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; |
1291 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
1292 | info = SHMEM_I(inode); |
1293 | memset(info, 0, (char *)inode - (char *)info); |
1294 | spin_lock_init(&info->lock); |
1295 | INIT_LIST_HEAD(&info->swaplist); |
1296 | |
1297 | switch (mode & S_IFMT) { |
1298 | default: |
1299 | inode->i_op = &shmem_special_inode_operations; |
1300 | init_special_inode(inode, mode, dev); |
1301 | break; |
1302 | case S_IFREG: |
1303 | inode->i_op = &shmem_inode_operations; |
1304 | inode->i_fop = &shmem_file_operations; |
1305 | mpol_shared_policy_init(&info->policy); |
1306 | break; |
1307 | case S_IFDIR: |
1308 | inode->i_nlink++; |
1309 | /* Some things misbehave if size == 0 on a directory */ |
1310 | inode->i_size = 2 * BOGO_DIRENT_SIZE; |
1311 | inode->i_op = &shmem_dir_inode_operations; |
1312 | inode->i_fop = &simple_dir_operations; |
1313 | break; |
1314 | case S_IFLNK: |
1315 | /* |
1316 | * Must not load anything in the rbtree, |
1317 | * mpol_free_shared_policy will not be called. |
1318 | */ |
1319 | mpol_shared_policy_init(&info->policy); |
1320 | break; |
1321 | } |
1322 | } else if (sbinfo) { |
1323 | spin_lock(&sbinfo->stat_lock); |
1324 | sbinfo->free_inodes++; |
1325 | spin_unlock(&sbinfo->stat_lock); |
1326 | } |
1327 | return inode; |
1328 | } |
1329 | |
1330 | #ifdef CONFIG_TMPFS |
1331 | |
1332 | static int shmem_set_size(struct shmem_sb_info *sbinfo, |
1333 | unsigned long max_blocks, unsigned long max_inodes) |
1334 | { |
1335 | int error; |
1336 | unsigned long blocks, inodes; |
1337 | |
1338 | spin_lock(&sbinfo->stat_lock); |
1339 | blocks = sbinfo->max_blocks - sbinfo->free_blocks; |
1340 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; |
1341 | error = -EINVAL; |
1342 | if (max_blocks < blocks) |
1343 | goto out; |
1344 | if (max_inodes < inodes) |
1345 | goto out; |
1346 | error = 0; |
1347 | sbinfo->max_blocks = max_blocks; |
1348 | sbinfo->free_blocks = max_blocks - blocks; |
1349 | sbinfo->max_inodes = max_inodes; |
1350 | sbinfo->free_inodes = max_inodes - inodes; |
1351 | out: |
1352 | spin_unlock(&sbinfo->stat_lock); |
1353 | return error; |
1354 | } |
1355 | |
1356 | static struct inode_operations shmem_symlink_inode_operations; |
1357 | static struct inode_operations shmem_symlink_inline_operations; |
1358 | |
1359 | /* |
1360 | * Normally tmpfs makes no use of shmem_prepare_write, but it |
1361 | * lets a tmpfs file be used read-write below the loop driver. |
1362 | */ |
1363 | static int |
1364 | shmem_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to) |
1365 | { |
1366 | struct inode *inode = page->mapping->host; |
1367 | return shmem_getpage(inode, page->index, &page, SGP_WRITE, NULL); |
1368 | } |
1369 | |
1370 | static ssize_t |
1371 | shmem_file_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) |
1372 | { |
1373 | struct inode *inode = file->f_dentry->d_inode; |
1374 | loff_t pos; |
1375 | unsigned long written; |
1376 | ssize_t err; |
1377 | |
1378 | if ((ssize_t) count < 0) |
1379 | return -EINVAL; |
1380 | |
1381 | if (!access_ok(VERIFY_READ, buf, count)) |
1382 | return -EFAULT; |
1383 | |
1384 | down(&inode->i_sem); |
1385 | |
1386 | pos = *ppos; |
1387 | written = 0; |
1388 | |
1389 | err = generic_write_checks(file, &pos, &count, 0); |
1390 | if (err || !count) |
1391 | goto out; |
1392 | |
1393 | err = remove_suid(file->f_dentry); |
1394 | if (err) |
1395 | goto out; |
1396 | |
1397 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; |
1398 | |
1399 | do { |
1400 | struct page *page = NULL; |
1401 | unsigned long bytes, index, offset; |
1402 | char *kaddr; |
1403 | int left; |
1404 | |
1405 | offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */ |
1406 | index = pos >> PAGE_CACHE_SHIFT; |
1407 | bytes = PAGE_CACHE_SIZE - offset; |
1408 | if (bytes > count) |
1409 | bytes = count; |
1410 | |
1411 | /* |
1412 | * We don't hold page lock across copy from user - |
1413 | * what would it guard against? - so no deadlock here. |
1414 | * But it still may be a good idea to prefault below. |
1415 | */ |
1416 | |
1417 | err = shmem_getpage(inode, index, &page, SGP_WRITE, NULL); |
1418 | if (err) |
1419 | break; |
1420 | |
1421 | left = bytes; |
1422 | if (PageHighMem(page)) { |
1423 | volatile unsigned char dummy; |
1424 | __get_user(dummy, buf); |
1425 | __get_user(dummy, buf + bytes - 1); |
1426 | |
1427 | kaddr = kmap_atomic(page, KM_USER0); |
1428 | left = __copy_from_user_inatomic(kaddr + offset, |
1429 | buf, bytes); |
1430 | kunmap_atomic(kaddr, KM_USER0); |
1431 | } |
1432 | if (left) { |
1433 | kaddr = kmap(page); |
1434 | left = __copy_from_user(kaddr + offset, buf, bytes); |
1435 | kunmap(page); |
1436 | } |
1437 | |
1438 | written += bytes; |
1439 | count -= bytes; |
1440 | pos += bytes; |
1441 | buf += bytes; |
1442 | if (pos > inode->i_size) |
1443 | i_size_write(inode, pos); |
1444 | |
1445 | flush_dcache_page(page); |
1446 | set_page_dirty(page); |
1447 | mark_page_accessed(page); |
1448 | page_cache_release(page); |
1449 | |
1450 | if (left) { |
1451 | pos -= left; |
1452 | written -= left; |
1453 | err = -EFAULT; |
1454 | break; |
1455 | } |
1456 | |
1457 | /* |
1458 | * Our dirty pages are not counted in nr_dirty, |
1459 | * and we do not attempt to balance dirty pages. |
1460 | */ |
1461 | |
1462 | cond_resched(); |
1463 | } while (count); |
1464 | |
1465 | *ppos = pos; |
1466 | if (written) |
1467 | err = written; |
1468 | out: |
1469 | up(&inode->i_sem); |
1470 | return err; |
1471 | } |
1472 | |
1473 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
1474 | { |
1475 | struct inode *inode = filp->f_dentry->d_inode; |
1476 | struct address_space *mapping = inode->i_mapping; |
1477 | unsigned long index, offset; |
1478 | |
1479 | index = *ppos >> PAGE_CACHE_SHIFT; |
1480 | offset = *ppos & ~PAGE_CACHE_MASK; |
1481 | |
1482 | for (;;) { |
1483 | struct page *page = NULL; |
1484 | unsigned long end_index, nr, ret; |
1485 | loff_t i_size = i_size_read(inode); |
1486 | |
1487 | end_index = i_size >> PAGE_CACHE_SHIFT; |
1488 | if (index > end_index) |
1489 | break; |
1490 | if (index == end_index) { |
1491 | nr = i_size & ~PAGE_CACHE_MASK; |
1492 | if (nr <= offset) |
1493 | break; |
1494 | } |
1495 | |
1496 | desc->error = shmem_getpage(inode, index, &page, SGP_READ, NULL); |
1497 | if (desc->error) { |
1498 | if (desc->error == -EINVAL) |
1499 | desc->error = 0; |
1500 | break; |
1501 | } |
1502 | |
1503 | /* |
1504 | * We must evaluate after, since reads (unlike writes) |
1505 | * are called without i_sem protection against truncate |
1506 | */ |
1507 | nr = PAGE_CACHE_SIZE; |
1508 | i_size = i_size_read(inode); |
1509 | end_index = i_size >> PAGE_CACHE_SHIFT; |
1510 | if (index == end_index) { |
1511 | nr = i_size & ~PAGE_CACHE_MASK; |
1512 | if (nr <= offset) { |
1513 | if (page) |
1514 | page_cache_release(page); |
1515 | break; |
1516 | } |
1517 | } |
1518 | nr -= offset; |
1519 | |
1520 | if (page) { |
1521 | /* |
1522 | * If users can be writing to this page using arbitrary |
1523 | * virtual addresses, take care about potential aliasing |
1524 | * before reading the page on the kernel side. |
1525 | */ |
1526 | if (mapping_writably_mapped(mapping)) |
1527 | flush_dcache_page(page); |
1528 | /* |
1529 | * Mark the page accessed if we read the beginning. |
1530 | */ |
1531 | if (!offset) |
1532 | mark_page_accessed(page); |
1533 | } else |
1534 | page = ZERO_PAGE(0); |
1535 | |
1536 | /* |
1537 | * Ok, we have the page, and it's up-to-date, so |
1538 | * now we can copy it to user space... |
1539 | * |
1540 | * The actor routine returns how many bytes were actually used.. |
1541 | * NOTE! This may not be the same as how much of a user buffer |
1542 | * we filled up (we may be padding etc), so we can only update |
1543 | * "pos" here (the actor routine has to update the user buffer |
1544 | * pointers and the remaining count). |
1545 | */ |
1546 | ret = actor(desc, page, offset, nr); |
1547 | offset += ret; |
1548 | index += offset >> PAGE_CACHE_SHIFT; |
1549 | offset &= ~PAGE_CACHE_MASK; |
1550 | |
1551 | page_cache_release(page); |
1552 | if (ret != nr || !desc->count) |
1553 | break; |
1554 | |
1555 | cond_resched(); |
1556 | } |
1557 | |
1558 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; |
1559 | file_accessed(filp); |
1560 | } |
1561 | |
1562 | static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) |
1563 | { |
1564 | read_descriptor_t desc; |
1565 | |
1566 | if ((ssize_t) count < 0) |
1567 | return -EINVAL; |
1568 | if (!access_ok(VERIFY_WRITE, buf, count)) |
1569 | return -EFAULT; |
1570 | if (!count) |
1571 | return 0; |
1572 | |
1573 | desc.written = 0; |
1574 | desc.count = count; |
1575 | desc.arg.buf = buf; |
1576 | desc.error = 0; |
1577 | |
1578 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); |
1579 | if (desc.written) |
1580 | return desc.written; |
1581 | return desc.error; |
1582 | } |
1583 | |
1584 | static ssize_t shmem_file_sendfile(struct file *in_file, loff_t *ppos, |
1585 | size_t count, read_actor_t actor, void *target) |
1586 | { |
1587 | read_descriptor_t desc; |
1588 | |
1589 | if (!count) |
1590 | return 0; |
1591 | |
1592 | desc.written = 0; |
1593 | desc.count = count; |
1594 | desc.arg.data = target; |
1595 | desc.error = 0; |
1596 | |
1597 | do_shmem_file_read(in_file, ppos, &desc, actor); |
1598 | if (desc.written) |
1599 | return desc.written; |
1600 | return desc.error; |
1601 | } |
1602 | |
1603 | static int shmem_statfs(struct super_block *sb, struct kstatfs *buf) |
1604 | { |
1605 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
1606 | |
1607 | buf->f_type = TMPFS_MAGIC; |
1608 | buf->f_bsize = PAGE_CACHE_SIZE; |
1609 | buf->f_namelen = NAME_MAX; |
1610 | if (sbinfo) { |
1611 | spin_lock(&sbinfo->stat_lock); |
1612 | buf->f_blocks = sbinfo->max_blocks; |
1613 | buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; |
1614 | buf->f_files = sbinfo->max_inodes; |
1615 | buf->f_ffree = sbinfo->free_inodes; |
1616 | spin_unlock(&sbinfo->stat_lock); |
1617 | } |
1618 | /* else leave those fields 0 like simple_statfs */ |
1619 | return 0; |
1620 | } |
1621 | |
1622 | /* |
1623 | * File creation. Allocate an inode, and we're done.. |
1624 | */ |
1625 | static int |
1626 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) |
1627 | { |
1628 | struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev); |
1629 | int error = -ENOSPC; |
1630 | |
1631 | if (inode) { |
1632 | if (dir->i_mode & S_ISGID) { |
1633 | inode->i_gid = dir->i_gid; |
1634 | if (S_ISDIR(mode)) |
1635 | inode->i_mode |= S_ISGID; |
1636 | } |
1637 | dir->i_size += BOGO_DIRENT_SIZE; |
1638 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
1639 | d_instantiate(dentry, inode); |
1640 | dget(dentry); /* Extra count - pin the dentry in core */ |
1641 | error = 0; |
1642 | } |
1643 | return error; |
1644 | } |
1645 | |
1646 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) |
1647 | { |
1648 | int error; |
1649 | |
1650 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) |
1651 | return error; |
1652 | dir->i_nlink++; |
1653 | return 0; |
1654 | } |
1655 | |
1656 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, |
1657 | struct nameidata *nd) |
1658 | { |
1659 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); |
1660 | } |
1661 | |
1662 | /* |
1663 | * Link a file.. |
1664 | */ |
1665 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) |
1666 | { |
1667 | struct inode *inode = old_dentry->d_inode; |
1668 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
1669 | |
1670 | /* |
1671 | * No ordinary (disk based) filesystem counts links as inodes; |
1672 | * but each new link needs a new dentry, pinning lowmem, and |
1673 | * tmpfs dentries cannot be pruned until they are unlinked. |
1674 | */ |
1675 | if (sbinfo) { |
1676 | spin_lock(&sbinfo->stat_lock); |
1677 | if (!sbinfo->free_inodes) { |
1678 | spin_unlock(&sbinfo->stat_lock); |
1679 | return -ENOSPC; |
1680 | } |
1681 | sbinfo->free_inodes--; |
1682 | spin_unlock(&sbinfo->stat_lock); |
1683 | } |
1684 | |
1685 | dir->i_size += BOGO_DIRENT_SIZE; |
1686 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
1687 | inode->i_nlink++; |
1688 | atomic_inc(&inode->i_count); /* New dentry reference */ |
1689 | dget(dentry); /* Extra pinning count for the created dentry */ |
1690 | d_instantiate(dentry, inode); |
1691 | return 0; |
1692 | } |
1693 | |
1694 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) |
1695 | { |
1696 | struct inode *inode = dentry->d_inode; |
1697 | |
1698 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) { |
1699 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
1700 | if (sbinfo) { |
1701 | spin_lock(&sbinfo->stat_lock); |
1702 | sbinfo->free_inodes++; |
1703 | spin_unlock(&sbinfo->stat_lock); |
1704 | } |
1705 | } |
1706 | |
1707 | dir->i_size -= BOGO_DIRENT_SIZE; |
1708 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
1709 | inode->i_nlink--; |
1710 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
1711 | return 0; |
1712 | } |
1713 | |
1714 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) |
1715 | { |
1716 | if (!simple_empty(dentry)) |
1717 | return -ENOTEMPTY; |
1718 | |
1719 | dir->i_nlink--; |
1720 | return shmem_unlink(dir, dentry); |
1721 | } |
1722 | |
1723 | /* |
1724 | * The VFS layer already does all the dentry stuff for rename, |
1725 | * we just have to decrement the usage count for the target if |
1726 | * it exists so that the VFS layer correctly free's it when it |
1727 | * gets overwritten. |
1728 | */ |
1729 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) |
1730 | { |
1731 | struct inode *inode = old_dentry->d_inode; |
1732 | int they_are_dirs = S_ISDIR(inode->i_mode); |
1733 | |
1734 | if (!simple_empty(new_dentry)) |
1735 | return -ENOTEMPTY; |
1736 | |
1737 | if (new_dentry->d_inode) { |
1738 | (void) shmem_unlink(new_dir, new_dentry); |
1739 | if (they_are_dirs) |
1740 | old_dir->i_nlink--; |
1741 | } else if (they_are_dirs) { |
1742 | old_dir->i_nlink--; |
1743 | new_dir->i_nlink++; |
1744 | } |
1745 | |
1746 | old_dir->i_size -= BOGO_DIRENT_SIZE; |
1747 | new_dir->i_size += BOGO_DIRENT_SIZE; |
1748 | old_dir->i_ctime = old_dir->i_mtime = |
1749 | new_dir->i_ctime = new_dir->i_mtime = |
1750 | inode->i_ctime = CURRENT_TIME; |
1751 | return 0; |
1752 | } |
1753 | |
1754 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) |
1755 | { |
1756 | int error; |
1757 | int len; |
1758 | struct inode *inode; |
1759 | struct page *page = NULL; |
1760 | char *kaddr; |
1761 | struct shmem_inode_info *info; |
1762 | |
1763 | len = strlen(symname) + 1; |
1764 | if (len > PAGE_CACHE_SIZE) |
1765 | return -ENAMETOOLONG; |
1766 | |
1767 | inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0); |
1768 | if (!inode) |
1769 | return -ENOSPC; |
1770 | |
1771 | info = SHMEM_I(inode); |
1772 | inode->i_size = len-1; |
1773 | if (len <= (char *)inode - (char *)info) { |
1774 | /* do it inline */ |
1775 | memcpy(info, symname, len); |
1776 | inode->i_op = &shmem_symlink_inline_operations; |
1777 | } else { |
1778 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); |
1779 | if (error) { |
1780 | iput(inode); |
1781 | return error; |
1782 | } |
1783 | inode->i_op = &shmem_symlink_inode_operations; |
1784 | kaddr = kmap_atomic(page, KM_USER0); |
1785 | memcpy(kaddr, symname, len); |
1786 | kunmap_atomic(kaddr, KM_USER0); |
1787 | set_page_dirty(page); |
1788 | page_cache_release(page); |
1789 | } |
1790 | if (dir->i_mode & S_ISGID) |
1791 | inode->i_gid = dir->i_gid; |
1792 | dir->i_size += BOGO_DIRENT_SIZE; |
1793 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; |
1794 | d_instantiate(dentry, inode); |
1795 | dget(dentry); |
1796 | return 0; |
1797 | } |
1798 | |
1799 | static int shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
1800 | { |
1801 | nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode)); |
1802 | return 0; |
1803 | } |
1804 | |
1805 | static int shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1806 | { |
1807 | struct page *page = NULL; |
1808 | int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); |
1809 | nd_set_link(nd, res ? ERR_PTR(res) : kmap(page)); |
1810 | return 0; |
1811 | } |
1812 | |
1813 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd) |
1814 | { |
1815 | if (!IS_ERR(nd_get_link(nd))) { |
1816 | struct page *page; |
1817 | |
1818 | page = find_get_page(dentry->d_inode->i_mapping, 0); |
1819 | if (!page) |
1820 | BUG(); |
1821 | kunmap(page); |
1822 | mark_page_accessed(page); |
1823 | page_cache_release(page); |
1824 | page_cache_release(page); |
1825 | } |
1826 | } |
1827 | |
1828 | static struct inode_operations shmem_symlink_inline_operations = { |
1829 | .readlink = generic_readlink, |
1830 | .follow_link = shmem_follow_link_inline, |
1831 | #ifdef CONFIG_TMPFS_XATTR |
1832 | .setxattr = generic_setxattr, |
1833 | .getxattr = generic_getxattr, |
1834 | .listxattr = generic_listxattr, |
1835 | .removexattr = generic_removexattr, |
1836 | #endif |
1837 | }; |
1838 | |
1839 | static struct inode_operations shmem_symlink_inode_operations = { |
1840 | .truncate = shmem_truncate, |
1841 | .readlink = generic_readlink, |
1842 | .follow_link = shmem_follow_link, |
1843 | .put_link = shmem_put_link, |
1844 | #ifdef CONFIG_TMPFS_XATTR |
1845 | .setxattr = generic_setxattr, |
1846 | .getxattr = generic_getxattr, |
1847 | .listxattr = generic_listxattr, |
1848 | .removexattr = generic_removexattr, |
1849 | #endif |
1850 | }; |
1851 | |
1852 | static int shmem_parse_options(char *options, int *mode, uid_t *uid, gid_t *gid, unsigned long *blocks, unsigned long *inodes) |
1853 | { |
1854 | char *this_char, *value, *rest; |
1855 | |
1856 | while ((this_char = strsep(&options, ",")) != NULL) { |
1857 | if (!*this_char) |
1858 | continue; |
1859 | if ((value = strchr(this_char,'=')) != NULL) { |
1860 | *value++ = 0; |
1861 | } else { |
1862 | printk(KERN_ERR |
1863 | "tmpfs: No value for mount option '%s'\n", |
1864 | this_char); |
1865 | return 1; |
1866 | } |
1867 | |
1868 | if (!strcmp(this_char,"size")) { |
1869 | unsigned long long size; |
1870 | size = memparse(value,&rest); |
1871 | if (*rest == '%') { |
1872 | size <<= PAGE_SHIFT; |
1873 | size *= totalram_pages; |
1874 | do_div(size, 100); |
1875 | rest++; |
1876 | } |
1877 | if (*rest) |
1878 | goto bad_val; |
1879 | *blocks = size >> PAGE_CACHE_SHIFT; |
1880 | } else if (!strcmp(this_char,"nr_blocks")) { |
1881 | *blocks = memparse(value,&rest); |
1882 | if (*rest) |
1883 | goto bad_val; |
1884 | } else if (!strcmp(this_char,"nr_inodes")) { |
1885 | *inodes = memparse(value,&rest); |
1886 | if (*rest) |
1887 | goto bad_val; |
1888 | } else if (!strcmp(this_char,"mode")) { |
1889 | if (!mode) |
1890 | continue; |
1891 | *mode = simple_strtoul(value,&rest,8); |
1892 | if (*rest) |
1893 | goto bad_val; |
1894 | } else if (!strcmp(this_char,"uid")) { |
1895 | if (!uid) |
1896 | continue; |
1897 | *uid = simple_strtoul(value,&rest,0); |
1898 | if (*rest) |
1899 | goto bad_val; |
1900 | } else if (!strcmp(this_char,"gid")) { |
1901 | if (!gid) |
1902 | continue; |
1903 | *gid = simple_strtoul(value,&rest,0); |
1904 | if (*rest) |
1905 | goto bad_val; |
1906 | } else { |
1907 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", |
1908 | this_char); |
1909 | return 1; |
1910 | } |
1911 | } |
1912 | return 0; |
1913 | |
1914 | bad_val: |
1915 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", |
1916 | value, this_char); |
1917 | return 1; |
1918 | |
1919 | } |
1920 | |
1921 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) |
1922 | { |
1923 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
1924 | unsigned long max_blocks = 0; |
1925 | unsigned long max_inodes = 0; |
1926 | |
1927 | if (sbinfo) { |
1928 | max_blocks = sbinfo->max_blocks; |
1929 | max_inodes = sbinfo->max_inodes; |
1930 | } |
1931 | if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks, &max_inodes)) |
1932 | return -EINVAL; |
1933 | /* Keep it simple: disallow limited <-> unlimited remount */ |
1934 | if ((max_blocks || max_inodes) == !sbinfo) |
1935 | return -EINVAL; |
1936 | /* But allow the pointless unlimited -> unlimited remount */ |
1937 | if (!sbinfo) |
1938 | return 0; |
1939 | return shmem_set_size(sbinfo, max_blocks, max_inodes); |
1940 | } |
1941 | #endif |
1942 | |
1943 | static void shmem_put_super(struct super_block *sb) |
1944 | { |
1945 | kfree(sb->s_fs_info); |
1946 | sb->s_fs_info = NULL; |
1947 | } |
1948 | |
1949 | #ifdef CONFIG_TMPFS_XATTR |
1950 | static struct xattr_handler *shmem_xattr_handlers[]; |
1951 | #else |
1952 | #define shmem_xattr_handlers NULL |
1953 | #endif |
1954 | |
1955 | static int shmem_fill_super(struct super_block *sb, |
1956 | void *data, int silent) |
1957 | { |
1958 | struct inode *inode; |
1959 | struct dentry *root; |
1960 | int mode = S_IRWXUGO | S_ISVTX; |
1961 | uid_t uid = current->fsuid; |
1962 | gid_t gid = current->fsgid; |
1963 | int err = -ENOMEM; |
1964 | |
1965 | #ifdef CONFIG_TMPFS |
1966 | unsigned long blocks = 0; |
1967 | unsigned long inodes = 0; |
1968 | |
1969 | /* |
1970 | * Per default we only allow half of the physical ram per |
1971 | * tmpfs instance, limiting inodes to one per page of lowmem; |
1972 | * but the internal instance is left unlimited. |
1973 | */ |
1974 | if (!(sb->s_flags & MS_NOUSER)) { |
1975 | blocks = totalram_pages / 2; |
1976 | inodes = totalram_pages - totalhigh_pages; |
1977 | if (inodes > blocks) |
1978 | inodes = blocks; |
1979 | |
1980 | if (shmem_parse_options(data, &mode, |
1981 | &uid, &gid, &blocks, &inodes)) |
1982 | return -EINVAL; |
1983 | } |
1984 | |
1985 | if (blocks || inodes) { |
1986 | struct shmem_sb_info *sbinfo; |
1987 | sbinfo = kmalloc(sizeof(struct shmem_sb_info), GFP_KERNEL); |
1988 | if (!sbinfo) |
1989 | return -ENOMEM; |
1990 | sb->s_fs_info = sbinfo; |
1991 | spin_lock_init(&sbinfo->stat_lock); |
1992 | sbinfo->max_blocks = blocks; |
1993 | sbinfo->free_blocks = blocks; |
1994 | sbinfo->max_inodes = inodes; |
1995 | sbinfo->free_inodes = inodes; |
1996 | } |
1997 | sb->s_xattr = shmem_xattr_handlers; |
1998 | #else |
1999 | sb->s_flags |= MS_NOUSER; |
2000 | #endif |
2001 | |
2002 | sb->s_maxbytes = SHMEM_MAX_BYTES; |
2003 | sb->s_blocksize = PAGE_CACHE_SIZE; |
2004 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; |
2005 | sb->s_magic = TMPFS_MAGIC; |
2006 | sb->s_op = &shmem_ops; |
2007 | inode = shmem_get_inode(sb, S_IFDIR | mode, 0); |
2008 | if (!inode) |
2009 | goto failed; |
2010 | inode->i_uid = uid; |
2011 | inode->i_gid = gid; |
2012 | root = d_alloc_root(inode); |
2013 | if (!root) |
2014 | goto failed_iput; |
2015 | sb->s_root = root; |
2016 | return 0; |
2017 | |
2018 | failed_iput: |
2019 | iput(inode); |
2020 | failed: |
2021 | shmem_put_super(sb); |
2022 | return err; |
2023 | } |
2024 | |
2025 | static kmem_cache_t *shmem_inode_cachep; |
2026 | |
2027 | static struct inode *shmem_alloc_inode(struct super_block *sb) |
2028 | { |
2029 | struct shmem_inode_info *p; |
2030 | p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, SLAB_KERNEL); |
2031 | if (!p) |
2032 | return NULL; |
2033 | return &p->vfs_inode; |
2034 | } |
2035 | |
2036 | static void shmem_destroy_inode(struct inode *inode) |
2037 | { |
2038 | if ((inode->i_mode & S_IFMT) == S_IFREG) { |
2039 | /* only struct inode is valid if it's an inline symlink */ |
2040 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); |
2041 | } |
2042 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); |
2043 | } |
2044 | |
2045 | static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags) |
2046 | { |
2047 | struct shmem_inode_info *p = (struct shmem_inode_info *) foo; |
2048 | |
2049 | if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == |
2050 | SLAB_CTOR_CONSTRUCTOR) { |
2051 | inode_init_once(&p->vfs_inode); |
2052 | } |
2053 | } |
2054 | |
2055 | static int init_inodecache(void) |
2056 | { |
2057 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", |
2058 | sizeof(struct shmem_inode_info), |
2059 | 0, 0, init_once, NULL); |
2060 | if (shmem_inode_cachep == NULL) |
2061 | return -ENOMEM; |
2062 | return 0; |
2063 | } |
2064 | |
2065 | static void destroy_inodecache(void) |
2066 | { |
2067 | if (kmem_cache_destroy(shmem_inode_cachep)) |
2068 | printk(KERN_INFO "shmem_inode_cache: not all structures were freed\n"); |
2069 | } |
2070 | |
2071 | static struct address_space_operations shmem_aops = { |
2072 | .writepage = shmem_writepage, |
2073 | .set_page_dirty = __set_page_dirty_nobuffers, |
2074 | #ifdef CONFIG_TMPFS |
2075 | .prepare_write = shmem_prepare_write, |
2076 | .commit_write = simple_commit_write, |
2077 | #endif |
2078 | }; |
2079 | |
2080 | static struct file_operations shmem_file_operations = { |
2081 | .mmap = shmem_mmap, |
2082 | #ifdef CONFIG_TMPFS |
2083 | .llseek = generic_file_llseek, |
2084 | .read = shmem_file_read, |
2085 | .write = shmem_file_write, |
2086 | .fsync = simple_sync_file, |
2087 | .sendfile = shmem_file_sendfile, |
2088 | #endif |
2089 | }; |
2090 | |
2091 | static struct inode_operations shmem_inode_operations = { |
2092 | .truncate = shmem_truncate, |
2093 | .setattr = shmem_notify_change, |
2094 | #ifdef CONFIG_TMPFS_XATTR |
2095 | .setxattr = generic_setxattr, |
2096 | .getxattr = generic_getxattr, |
2097 | .listxattr = generic_listxattr, |
2098 | .removexattr = generic_removexattr, |
2099 | #endif |
2100 | }; |
2101 | |
2102 | static struct inode_operations shmem_dir_inode_operations = { |
2103 | #ifdef CONFIG_TMPFS |
2104 | .create = shmem_create, |
2105 | .lookup = simple_lookup, |
2106 | .link = shmem_link, |
2107 | .unlink = shmem_unlink, |
2108 | .symlink = shmem_symlink, |
2109 | .mkdir = shmem_mkdir, |
2110 | .rmdir = shmem_rmdir, |
2111 | .mknod = shmem_mknod, |
2112 | .rename = shmem_rename, |
2113 | #ifdef CONFIG_TMPFS_XATTR |
2114 | .setxattr = generic_setxattr, |
2115 | .getxattr = generic_getxattr, |
2116 | .listxattr = generic_listxattr, |
2117 | .removexattr = generic_removexattr, |
2118 | #endif |
2119 | #endif |
2120 | }; |
2121 | |
2122 | static struct inode_operations shmem_special_inode_operations = { |
2123 | #ifdef CONFIG_TMPFS_XATTR |
2124 | .setxattr = generic_setxattr, |
2125 | .getxattr = generic_getxattr, |
2126 | .listxattr = generic_listxattr, |
2127 | .removexattr = generic_removexattr, |
2128 | #endif |
2129 | }; |
2130 | |
2131 | static struct super_operations shmem_ops = { |
2132 | .alloc_inode = shmem_alloc_inode, |
2133 | .destroy_inode = shmem_destroy_inode, |
2134 | #ifdef CONFIG_TMPFS |
2135 | .statfs = shmem_statfs, |
2136 | .remount_fs = shmem_remount_fs, |
2137 | #endif |
2138 | .delete_inode = shmem_delete_inode, |
2139 | .drop_inode = generic_delete_inode, |
2140 | .put_super = shmem_put_super, |
2141 | }; |
2142 | |
2143 | static struct vm_operations_struct shmem_vm_ops = { |
2144 | .nopage = shmem_nopage, |
2145 | .populate = shmem_populate, |
2146 | #ifdef CONFIG_NUMA |
2147 | .set_policy = shmem_set_policy, |
2148 | .get_policy = shmem_get_policy, |
2149 | #endif |
2150 | }; |
2151 | |
2152 | |
2153 | #ifdef CONFIG_TMPFS_SECURITY |
2154 | |
2155 | static size_t shmem_xattr_security_list(struct inode *inode, char *list, size_t list_len, |
2156 | const char *name, size_t name_len) |
2157 | { |
2158 | return security_inode_listsecurity(inode, list, list_len); |
2159 | } |
2160 | |
2161 | static int shmem_xattr_security_get(struct inode *inode, const char *name, void *buffer, size_t size) |
2162 | { |
2163 | if (strcmp(name, "") == 0) |
2164 | return -EINVAL; |
2165 | return security_inode_getsecurity(inode, name, buffer, size); |
2166 | } |
2167 | |
2168 | static int shmem_xattr_security_set(struct inode *inode, const char *name, const void *value, size_t size, int flags) |
2169 | { |
2170 | if (strcmp(name, "") == 0) |
2171 | return -EINVAL; |
2172 | return security_inode_setsecurity(inode, name, value, size, flags); |
2173 | } |
2174 | |
2175 | static struct xattr_handler shmem_xattr_security_handler = { |
2176 | .prefix = XATTR_SECURITY_PREFIX, |
2177 | .list = shmem_xattr_security_list, |
2178 | .get = shmem_xattr_security_get, |
2179 | .set = shmem_xattr_security_set, |
2180 | }; |
2181 | |
2182 | #endif /* CONFIG_TMPFS_SECURITY */ |
2183 | |
2184 | #ifdef CONFIG_TMPFS_XATTR |
2185 | |
2186 | static struct xattr_handler *shmem_xattr_handlers[] = { |
2187 | #ifdef CONFIG_TMPFS_SECURITY |
2188 | &shmem_xattr_security_handler, |
2189 | #endif |
2190 | NULL |
2191 | }; |
2192 | |
2193 | #endif /* CONFIG_TMPFS_XATTR */ |
2194 | |
2195 | static struct super_block *shmem_get_sb(struct file_system_type *fs_type, |
2196 | int flags, const char *dev_name, void *data) |
2197 | { |
2198 | return get_sb_nodev(fs_type, flags, data, shmem_fill_super); |
2199 | } |
2200 | |
2201 | static struct file_system_type tmpfs_fs_type = { |
2202 | .owner = THIS_MODULE, |
2203 | .name = "tmpfs", |
2204 | .get_sb = shmem_get_sb, |
2205 | .kill_sb = kill_litter_super, |
2206 | }; |
2207 | static struct vfsmount *shm_mnt; |
2208 | |
2209 | static int __init init_tmpfs(void) |
2210 | { |
2211 | int error; |
2212 | |
2213 | error = init_inodecache(); |
2214 | if (error) |
2215 | goto out3; |
2216 | |
2217 | error = register_filesystem(&tmpfs_fs_type); |
2218 | if (error) { |
2219 | printk(KERN_ERR "Could not register tmpfs\n"); |
2220 | goto out2; |
2221 | } |
2222 | #ifdef CONFIG_TMPFS |
2223 | devfs_mk_dir("shm"); |
2224 | #endif |
2225 | shm_mnt = do_kern_mount(tmpfs_fs_type.name, MS_NOUSER, |
2226 | tmpfs_fs_type.name, NULL); |
2227 | if (IS_ERR(shm_mnt)) { |
2228 | error = PTR_ERR(shm_mnt); |
2229 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); |
2230 | goto out1; |
2231 | } |
2232 | return 0; |
2233 | |
2234 | out1: |
2235 | unregister_filesystem(&tmpfs_fs_type); |
2236 | out2: |
2237 | destroy_inodecache(); |
2238 | out3: |
2239 | shm_mnt = ERR_PTR(error); |
2240 | return error; |
2241 | } |
2242 | module_init(init_tmpfs) |
2243 | |
2244 | /* |
2245 | * shmem_file_setup - get an unlinked file living in tmpfs |
2246 | * |
2247 | * @name: name for dentry (to be seen in /proc/<pid>/maps |
2248 | * @size: size to be set for the file |
2249 | * |
2250 | */ |
2251 | struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) |
2252 | { |
2253 | int error; |
2254 | struct file *file; |
2255 | struct inode *inode; |
2256 | struct dentry *dentry, *root; |
2257 | struct qstr this; |
2258 | |
2259 | if (IS_ERR(shm_mnt)) |
2260 | return (void *)shm_mnt; |
2261 | |
2262 | if (size < 0 || size > SHMEM_MAX_BYTES) |
2263 | return ERR_PTR(-EINVAL); |
2264 | |
2265 | if (shmem_acct_size(flags, size)) |
2266 | return ERR_PTR(-ENOMEM); |
2267 | |
2268 | error = -ENOMEM; |
2269 | this.name = name; |
2270 | this.len = strlen(name); |
2271 | this.hash = 0; /* will go */ |
2272 | root = shm_mnt->mnt_root; |
2273 | dentry = d_alloc(root, &this); |
2274 | if (!dentry) |
2275 | goto put_memory; |
2276 | |
2277 | error = -ENFILE; |
2278 | file = get_empty_filp(); |
2279 | if (!file) |
2280 | goto put_dentry; |
2281 | |
2282 | error = -ENOSPC; |
2283 | inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0); |
2284 | if (!inode) |
2285 | goto close_file; |
2286 | |
2287 | SHMEM_I(inode)->flags = flags & VM_ACCOUNT; |
2288 | d_instantiate(dentry, inode); |
2289 | inode->i_size = size; |
2290 | inode->i_nlink = 0; /* It is unlinked */ |
2291 | file->f_vfsmnt = mntget(shm_mnt); |
2292 | file->f_dentry = dentry; |
2293 | file->f_mapping = inode->i_mapping; |
2294 | file->f_op = &shmem_file_operations; |
2295 | file->f_mode = FMODE_WRITE | FMODE_READ; |
2296 | return file; |
2297 | |
2298 | close_file: |
2299 | put_filp(file); |
2300 | put_dentry: |
2301 | dput(dentry); |
2302 | put_memory: |
2303 | shmem_unacct_size(flags, size); |
2304 | return ERR_PTR(error); |
2305 | } |
2306 | |
2307 | /* |
2308 | * shmem_zero_setup - setup a shared anonymous mapping |
2309 | * |
2310 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff |
2311 | */ |
2312 | int shmem_zero_setup(struct vm_area_struct *vma) |
2313 | { |
2314 | struct file *file; |
2315 | loff_t size = vma->vm_end - vma->vm_start; |
2316 | |
2317 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); |
2318 | if (IS_ERR(file)) |
2319 | return PTR_ERR(file); |
2320 | |
2321 | if (vma->vm_file) |
2322 | fput(vma->vm_file); |
2323 | vma->vm_file = file; |
2324 | vma->vm_ops = &shmem_vm_ops; |
2325 | return 0; |
2326 | } |